Tau lepton production and decay to hadronic final states
offer the unique possibility for studying low energy hadron dynamics
and the weak couplings of the tau at the same time.
Eventually one may even be sensitive to signals of physics
beyond the Standard Model, like deviations from the
V-A structure of the charged currents, or even discover CP violation.
Tau polarization and the polarization of the decay products may be
crucial for these investigations.